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(No Model.)

G E. HART.

MAINSPRING BARRBL POR WATGHES. No. 338.960. 'Patented Mar. 30 1886.

' UNITED STATES PATENT OFFICE..

GEORGE E'. HART, OF XVATERBURY, CONNECTICUT, ASSIGNOR TO THE XVATERBURYWATCH COMPANY, OF SAME PLACE.

MAINSPRING-BARREL FOR WATCHES.

EPECIFICATION forming part of Letters Patent Ne. 338,960, dated March30, 1886.

Application filed July 14, 1885. Serial No. 171.592. (No model.)

To aZZ whom, 't may concern:

Be it known that I, GEORGE E. HART, of aterbury, in the county of NewHaven, and in the State of Connecticut, have invented certainImprovements in lVIainspring-Barrels for watches and in the Method ofConstructing the Same; and I do hereby declare that the following is afull, clear, and exact description thereof, reference being had to theacconpanying drawings, in which- Figure 1 is a perspective View of ablank for aspring-barrel after it has passed through the firstoperation. Fig. 2 is a like view of the same after having been operatedupon by the second pair of dies. Fig. 3 is a perspective View of saidblank after the operation of the third pair of dies. Fig. 4 is a likeView of the completed barrel, and Fig. 5 is a central cross-section ofthe same.

Letters of like name and kind refer to like parts in each of thefigures.

The design of ny invention is 'to lessen the expense and to increase thestrength and durability of mainspring-barrels for watches; and to thisend it consists, principally, as a new article of nanufacture, in ablank nainspringbarrel which is constructed from sheet metal by drawingor pressing, and is provided upon its periphery with a radial flangefrom which to form gear-teeth, substantiall y as and for the purposehereinafter specified.

It consists, further, as a new article of nanufacture, in a blankmainspring-barrel which is constructed from sheet netal by drawing orpressing, and is provided upon its periphery with a radial flange fromwhich to form gearteeth, and within its interior with a raised centralhub, substantially as and for the purpose shown.

In the carrying of ny invention into practice I cut froni a sheet ofmetal a disk, A, which at the same time or by a subsequent operation ofdies is given a slight cup shape, as seen in Fig. 2. The blank A is nextsubjected to the action of a pair of dies, which increases the height ofthe side wall, a, after which, by means of another pair of dies, saidwall is receive the edge of a cover the barrel is conr pleted. As theblank leaves the dies in the condition shown in Fig. 3, it is readilydistinguished froni a blank constructed by other means, and may be anarticle of sale for conipletion by the purchaser.

By my method of construction the barrel possesses much greater strengthand rigidity for a given weight than it would be possible to obtain bythe usual method of casting a blank and dressing it to shape withcuttingtools, and, in addition to such advantage, it can be produced fora fraction of the expense heretofore required and with less waste ofmaterial.

Having* thus fully set forth the nature and nerits of my invention, Iclaim 1. As a new article of nanufacture, a blank mainspring-barrelwhich is constructed from sheet metal by drawing or pressing, and isprovided upon its periphery with a radial fiange fron which to formgear-teeth, substantially as and for the purpose specified.

2. As a new article of manufacture, a blank mainspringbarrel which isconstructed froni sheet metal by drawing or pressing, and is providedupon its periphery with a radial flange from which to form gear-teeth,and within its interior with a raised central hub, substantially as andfor the purpose shown.

In testimony that I claim the foregoing I have hereunto set iny handthis 10th day of July, 1885.

GEORGE E. HART.

Witnesses:

CHARLES S. CHAPMAN, GEO. E. TERRY.

